1. Field of the Invention
The present invention relates to a digital broadcast signal receiving device for reproducing, recording, and recording and reproducing a video signal or an audio or voice signal or digital information transmitted through digital broadcasts in the form of superimposing of an encryption key or a copy control signal thereon, and a recording and reproducing device for the digital broadcast signal.
2. Description of the Related Art
A pay-television broadcast has means for scrambling a signal therefor and allowing only a receiver to decryption its scramble and is constructed so as to be capable of receiving the decrypted signal.
This type of scramble technique has been done in cable television or the like. However, the present technique has come into wider use as it comes to a digital broadcast using a satellite.
As conventional analog systems, there are known a line rotation system for replacing the front and back of analog video signal with each other for every scanning line at random and scrambling it, and a line permutation system for dividing a video signal into respective signals so that the screen is cut and divided in the horizontal direction and permuting the divided video signals in the vertical direction.
As the digital broadcast using the satellite began, a system for encrypting a signal itself has spread so as to make it more difficult to decrypt or decode the signal, without having to use such an analog system.
Thus, when such an encrypted pay broadcast is recorded, it is necessary to construct a system of such a type that a specific process is performed on the recording device side and the pay broadcast can be recorded only by the proper receiver or a pay-broadcast contractor.
A copy control system proposed from this point of view has not yet come into being. The present invention has been invented in consideration of this viewpoint.
An object of the present invention is to provide a proper receiver as the object with means for controlling recording.
An another object of the present invention is to provide a receiving device, a recording device, and a recording and reproducing device for a digital broadcast signal, wherein the recording device performs authenticating work between the recording device and the receiving device (hereinafter abbreviated as xe2x80x9cSTB: Set Top Boxxe2x80x9d) in a pay broadcast thereby to confirm that a receiver is proper, followed by falling into a recording operation.
A further object of the present invention is to provide a receiving device, a recording device, and a recording and reproducing device wherein in order to perform encryption (scramble process) according to a device ID signal inherent in a receiver and determine even upon reproduction whether or not a recording medium is an illegally-copied recording medium, an attribute signal contained in a reproduced signal is detected and a reproducing operation is stopped according to the attribute signal.
According to one aspect of this invention, for achieving the above objects, there is provided a receiving device comprising a signal demodulator circuit for demodulating an encrypted video signal and attribute information including information for decoding an encryption, an attribute information identifying circuit for identifying and outputting the attribute information, and a descramble circuit for unlocking scrambling of the video signal obtained from the signal demodulator circuit according to the output obtained from the attribute information identifying circuit and wherein the output of the descramble circuit is outputted for recording. Further, the signal obtained from the attribute information identifying circuit is outputted to a recording device to perform copy control. There is also provided a re-scramble circuit for effecting re-scrambling on the descrambled video signal according to the attribute information obtained from the attribute information identifying circuit. In the receiving device, an electronic watermark processing circuit is provided and a CGMS signal obtained from the electronic watermark processing circuit is outputted to a recording device to control copying of the recording device. Further, in the receiving device, a device ID generating circuit for generating an intrinsic device ID signal is provided and a re-scramble circuit for effecting re-scrambling on the descrambled video signal according to the device ID signal obtained from the device ID generating circuit is provided. The attribute information identifying circuit includes an attribute information detection circuit for detecting attribute information, and an encryption key decoding circuit for decoding the encryption key detected by the attribute information detection circuit. The encryption key obtained from the output of the encryption key decoding circuit is supplied to the descramble circuit. The attribute information detection circuit detects a CGMS signal contained in the attribute information and outputs the same to a recording device as a copy control signal. The receiving device includes an MPEG decode circuit for decoding an MPEG-compressed video signal and a video encode circuit for converting the decoded video signal to a standard television signal. The receiving device includes a stream circuit for converting the re-scrambled signal to a stream and outputting the same therefrom. Further, a modem connected to a telephone line is provided and obtains the device ID signal through the telephone line.
According to another aspect of this invention, for achieving the above objects, there is provided a receiving device comprising a signal demodulator circuit for demodulating an encrypted video signal and attribute information, a signal processing circuit for unlocking an encryption of the demodulated signal, a re-scramble circuit for scrambling the encryption-set free video signal again, means for outputting the re-scrambled video signal to a recording device for recording, and an attribute information identifying circuit for outputting a copy control signal for inputting to the recording device. Further, the signal processing circuit outputs an analog television signal to a television receiver.
According to a further aspect of this invention, there is provided a receiving device comprising a signal demodulator circuit for demodulating an encrypted video signal and attribute information including each encryption key and each channel key indicative of a broadcast channel, a channel key detection circuit for detecting a channel key from the attribute information, an encryption key detection circuit for detecting an encryption key from the attribute information, a device ID generating circuit for generating an intrinsic device ID signal, a channel key selection circuit for selecting a channel key for a receivable channel according to the device ID signal and outputting the same therefrom, a decryption circuit (an encryption decoding circuit) for outputting a decryption key from the channel key outputted from the channel key selection circuit and the encryption key, a descramble circuit for unlocking scrambling of the video signal obtained from the signal demodulator circuit, based on the decryption key, and a re-scramble circuit for re-scrambling the descrambled video signal using the decryption key, and wherein the output of the re-scramble circuit is outputted for recording. In the present receiving device, a format conversion circuit is provided and performs format conversion for converting the descrambled video signal to a format which matches with a recording medium to record the video signal therein.
According to a still further aspect of this invention, for achieving the above objects, there is provided a recording and reproducing device comprising a recording and reproducing portion for recording a video signal scrambled in accordance with an intrinsic device ID signal, a device ID generating circuit for generating an intrinsic device ID signal, and a device ID detection/coincidence circuit for detecting a device ID signal contained in the recorded and reproduced video signal, making a decision as to the coincidence between the detected device ID signal and the device ID signal outputted from the device ID generating circuit, and allowing the passage of the reproduced video signal when they coincide with each other. Output means for supplying the output of the device ID generating circuit to a receiver for outputting a video signal scrambled according to an intrinsic device ID signal is provided. The recording and reproducing device includes a descramble circuit for releasing scrambling, an MPEG decode circuit for decoding an MPEG-compressed video signal and a video encode circuit for converting the video signal to a standard television signal.
According to a still further aspect of this invention, there is provided a recording and reproducing device comprising a recording and reproducing portion for recording a video signal scrambled according to an intrinsic device ID signal, a device ID generating circuit for generating an intrinsic device ID signal, and a descramble circuit for effecting descrambling on the video signal reproduced from the recording and reproducing portion using the device ID signal. The recording and reproducing device is provided with an MPEG decode circuit for decoding an MPEG-compressed video signal obtained from the descramble circuit, and an electronic watermark detection circuit for detecting electronic watermark information for performing copy control from the output of the descramble circuit and wherein upon copy prohibition, the MPEG decode circuit is deactivated according to the electronic watermark information.
According to a still further aspect of this invention, there is provided a recording and reproducing device comprising means for inputting therein an input signal including a video signal scrambled according to an intrinsic device ID signal, a device ID signal and updated copy control electronic watermark information, a device ID generating circuit for generating an intrinsic device ID signal, a descramble circuit for unscrambling the input signal by using the generated device ID signal, a recording and reproducing portion for recording the descrambled signal, an electronic watermark detection circuit for detecting the electronic watermark information from the descrambled signal, and means for controlling the recording of the recording and reproducing portion based on the electronic watermark information. The device ID signal obtained from the device ID generating circuit is supplied to the recording and reproducing portion where the present device ID signal makes coincidence with the device ID signal obtained from the descramble circuit, and when they coincide with each other, the recording of the recording and reproducing portion is allowed. Further, the output of the device ID detection/coincidence circuit is supplied to the MPEG decode circuit. Thus, when the device ID signals coincide with each other, the MPEG decode circuit is activated whereas when they do not coincide with each other, the MPEG decode circuit is deactivated. The recording and reproducing device is provided with a re-scramble circuit which re-scrambles the output of the MPEG decode circuit according to the device ID signal obtained from the device ID detection/coincidence circuit and outputs the re-scrambled output to another recording and reproducing device for recording.
According to a still further aspect of this invention, there is provided a receiving/recording-reproducing system comprising means for receiving an encrypted video signal and a signal including a decryption key related to the video signal, and a decryption circuit for decoding the video signal using the decryption key. The receiving/recording-reproducing system is provided with recording means for recording the video signal inputted thereto, and a control signal reading circuit for reading a control signal from the signal related to the video signal, whereby a recording operation of the recording means is controlled according to the control signal. Further, the receiving/recording-reproducing system is provided with an electronic watermark detection circuit for detecting electronic watermark information superimposed on the video signal and recorded, a decoding circuit for decoding the output of the decryption circuit, a format conversion circuit for converting the output of the decoding circuit to a format, and recording means for recording the output of the format conversion circuit therein, whereby the recording of the recording means is controlled according to the output of the electronic watermark detection circuit.